assertEquals("444", paramMap.get("ccc.ddd"));
        assertNull(paramMap.get("cccDdd"));
        assertNull(paramMap.get("DccDdd"));
    }

    @Test
    public void test_snake_containsKey() {
        Map<Object, Object> paramMap = createSnakeMap();

        assertFalse(paramMap.containsKey("xxx"));
        assertTrue(paramMap.containsKey("aaa"));
        assertTrue(paramMap.containsKey("aaa_bbb"));